Dental composite filling materials typically contain a predominant amount of fillers, for example quartz, and a relatively small amount of a flowable monomer. Such composites typically further contain a photo initiator allowing the monomer to be polymerized through light energy. Therefore the dental composite filling materials may be applied in a cavity in a patient's tooth and light-cured after application in the patient's tooth.
Typically such dental composite filling materials exhibit a relatively high viscosity and therefore typically require high forces for dispensing from a dispensing device. A dispensing device for dispensing dental composite filling materials is for example disclosed in U.S. Pat. No. 7,128,246 B2. Such a device stores a portion of a dental composite filling material which can be extruded by displacing a piston within the device. The device can be coupled to a hand-held dispensing gun providing a relatively high force for displacing the piston via a hand operable leverage.
An alternative dispensing device for dental composite filling materials is disclosed in U.S. Design Pat. No. Des. 419,236. WO 2006/108085 A2 discloses a syringe delivery system for dispensing a highly viscous material through a syringe delivery opening. The system includes a syringe barrel having a delivery opening, a plunger including a threaded shaft that threadably engages the syringe barrel for selectively dispensing a viscous material through the delivery opening, and a plunger gripping member in gripping communication with the plunger that includes means for sealing the threaded shaft of the plunger so as to prevent contamination by foreign matter. The syringe has a sheath that covers the threaded shaft of the plunger so as to hide the plunger beneath the sheath. The sheath provides a sealed environment for the threaded shaft so as to prevent entrance or contamination by foreign matter.
Although a variety of dispensers for dental composite filling materials are available there is still a need for a dispenser which is easy to use, which accounts for hygiene requirements in dentistry and which helps maximizing shelf life of the dental material stored therein.